Buffers are general-purpose building blocks that are used extensively in electronic circuits. Ideally, a buffer has infinite input impedance, zero output impedance, and a voltage gain of 1 over all frequencies. The most popular form is an open loop buffer, which offers very wide bandwidth, high slew rate, high output drive current, and several other features, and uses the fewest number of parts. Open loop buffers have a major drawback, however, in the area of accuracy. The invention provides a buffer that offers improved accuracy over prior art buffers, yet maintains most of the benefits of the open loop buffers.